source-repository-package stanzas in conditionals don't work

[michaelpj]

e.g.

if impl(ghc >= 9.6)
  -- Version on Hackages does not compile with `ghc-9.6`
  -- https://github.com/haskell-foundation/foundation/issues/576
  source-repository-package
    type: git
    location: https://github.com/Topsii/foundation
    tag: d3136f4bb8b69e273535352620e53f2196941b35
    subdir:
      basement
      edge
      foundation

We fail to replace this, so even if you have a sha256map it fails trying to access the network.

Not surprising give out ad-hoc parser in Nix. Probably the best way to fix it is to continue pulling stuff into Haskell where we can use cabal's parser, cc @andreabedini

[andreabedini]

Yes, I am not surprised. Thanks for reporting this.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[michaelpj]

Wait, is this actually fixed? @andreabedini

[michaelpj]

The latest release of HLS has a conditional stanza for 9.8 that includes head.hackage, and as such isn't buildable (from the repository) with haskell.nix because of this issue.

[angerman]

@andreabedini for my understanding. The issue is an additional conditional compiler stanza, in the cabal.project file, which then ends up prohibiting us from going forward, even if it's completely irrelevant to the build?

[andreabedini]

It look like we just ignore it, so the example above would work with ghc < 9.6 (because cabal would skip that section and won't pull the srp) but it would fail on ghc >= 9.6 whether or not you add the -- sha256: xxx line to the srp.

[michaelpj]

Yes, exactly. The situation is:

• We don't replace it like we normally do
• If cabal doesn't use the body of the conditional, that's fine
• If cabal does use the body of the conditional, it all goes wrong because we haven't replaced it

[michaelpj]

This also applies to things like repository stanzas.